Modulation of the Directionality of Hole Transfer between the Base and the Sugar-Phosphate Backbone in DNA with the Number of Sulfur Atoms in the Phosphate Group.

This work shows that S atom substitution in phosphate controls the directionality of hole transfer processes between the base and sugar-phosphate backbone in DNA systems. The investigation combines synthesis, electron spin resonance (ESR) studies in supercooled homogeneous solution, pulse radiolysis in aqueous solution at ambient temperature, and density functional theory (DFT) calculations of in-house synthesized model compound dimethylphosphorothioate (DMTP(O)═S) and nucleotide (5'--methoxyphosphorothioyl-2'-deoxyguanosine (G-P(O)═S)). ESR investigations show that DMTP(O)═S reacts with Cl to form the σσ* adduct radical -P-S[Formula: see text]Cl, which subsequently reacts with DMTP(O)═S to produce [-P-S[Formula: see text]S-P-].

One Way Traffic: Base-to-Backbone Hole Transfer in Nucleoside Phosphorodithioate.

Invited for the cover of this issue are the groups of Roman Dembinski, Mehran Mostafavi, and Amitava Adhikary at the Polish Academy of Sciences, Université Paris-Saclay, and Oakland University. The image depicts a doughnut as a way of illustrating the hole transfer process. Read the full text of the article at 10.

One Way Traffic: Base-to-Backbone Hole Transfer in Nucleoside Phosphorodithioate.

The directionality of the hole-transfer processes between DNA backbone and base was investigated by using phosphorodithioate [P(S )=S] components. ESR spectroscopy in homogeneous frozen aqueous solutions and pulse radiolysis in aqueous solution at ambient temperature confirmed initial formation of G -P(S )=S. The ionization potential of G-P(S )=S was calculated to be slightly lower than that of guanine in 5'-dGMP.